Previous studies indicate that breast arterial calcification is evidence of general atherosclerotic vascular disease and it may be a useful marker of coronary artery disease. Breast arterical calcification can potentially be a useful tool for assessment of coronary artery disease in women. The purpose of this project is to quantify breast arterial calcium mass accurately using standard digital mammography. This project is supported by a $6.8 million grant from the National Heart, Lung & Blood Institute, involving more than 5,000 patients at nine Kaiser Permanente medical centers in California.